Vomitting

So, A made it to thirteen months with very minimal spitting up and only one vomiting incident (due to medication that di not agree with him).  Then all of a sudden, he has vomited three times in a week.  Each incident has occurred at around bedtime.  Last week, I attributed it to the introduction of mango.  He was fine for a week and then on Tuesday evening, I was feeding him dinner and all of a sudden at the end, he just let loose and threw up everything in his stomach.  I actually saw some bits of orange from breakfast in there! Poor kiddo.  Then he was fine for the rest of the evening and all day yesterday.  Good appetite, good spirits, no vomit.  Then last night, he had a normal dinner that he's eaten dozens of times.  Then we nursed before bed, as per usual.  We put him down in his crib and within about 2 minutes I head him gagging on the monitor.  By the time I got in there, he had already vomited all over himself.  And then proceeded to throw up twice more- again emptying his stomach.  Just like the night before, he was fine afterwards and this morning he wolfed down his usual breakfast.  I'm thinking that maybe he's just having to much to eat at the end of the day- though the amount hasn't changed much over the past two months or so.  He typically gets 4oz of WCM at 4:15/4:30, dinner at 6 and nursing at 6:45/7.  Maybe that's too much? Today, I cut back the WCM for daycare to 3oz.  But this kiddo needs all the calories he can get.  Does anyone have any advice or thoughts?  He doesn't seem to have a bug or appear sick.  I think I'm going to call the pedi today.